Add versions API type

src/index.ts

@@ -7,5 +7,6 @@ export { Service, Stop } from './database/timetable'
 export { User } from './database/user'
 
 // Downstream API
+export { Versions } from './owlboardApi/versions'
 
 // Upstream API

src/owlboardApi/versions.ts

@@ -0,0 +1,7 @@
+interface Versions {
+    backend: string,
+    "db-manager": string,
+    "mq-client": string
+}
+
+export { Versions }